All Spaces

Scope

This document outlines three separate components of this benchmark. It is the hope that the participant will simulate all three components, but the participant is free to simulate any or all of the components.

This benchmark is open to participants of the Wakebench project using wake and, possibly, atmospheric boundary layer models. This is based on the actual operational Lillgrund wind farm in which there are multiple turbines interacting within an array. The benchmark aims to test a wake/atmospheric model to reproduce the power production observed at Lillgrund when wind is from a southwesterly, southeasterly, and northwesterly sector.

For the Southwest case, the sector is centered upon 222° aligned with rows A-H in which there is 4.3 rotor diameter (D) spacing. For the Southeast case, the sector is centered upon 120° aligned with rows 1-8 in which there is a 3.3 D spacing. For the Northwest case, the sector is centered upon the 300° direction aligned again with rows 1-8, with flow coming from the opposite direction of the Southeast case, with a 3.3 D spacing.

Scope

The benchmark is open to participants of the Wakebench project using wake and, possibly, atmospheric boundary layer models. This is a case based on the actual operational Lillgrund wind farm in which there are multiple turbines interacting within an array. This benchmark aims to test a wake/atmospheric model to reproduce the maximum power deficit of the second turbine in a row as a function of spacing and turbulence intensity.

Objectives

Demonstrate how wake models perform and capture the wake formation and merging process in the presence of atmospheric shear and turbulence within a large modern wind farm composed of modern multimegawatt turbines.

Data Accessibility

The benchmark is offered to participants of the IEA Task 31 Wakebench.

Input data

Site Description:

NOWITECH, ReaTHM (Real Time Hybrid Model testing) in MARINTEK ocean basin. A semisubmersible wind turbine will be tested in the ocean basin of MARINTEK, Trondheim, Norway. The model of the floating wind turbine will be anchored in the center of the basin. The mooring system is a spread mooring and the water depth is selected to be 200m. The wind will be modeled in the experiments by use of Hardware in the Loop setup where the wind is simulated in real time by use of Aerodyn. The aerodynamic loads in surge, roll, and yaw are then applied on the model by use of 6 actuators. The actuators apply forces by use of a motor-spring assembly. The model scale is 1:30. This scale will be suitable with respect to the quality of the waves, the model size and the handling of the models in the test set-up. The model tests with the floating offshore wind turbine are intended to take place during weeks 39 and 40 (i.e. by the end of September). Contact: Dr Madjid Karimirad Madjid.Karimirad@marintek.sintef.noThe test will be performed in the ocean basin of MARINTEK, Trondheim, Norway.

Unified mesoscale to wind turbine wake downscaling based on an open-source model chain

MesoWake is a project sponsored by the European Commission's within an FP7 International Outgoing Marie Curie Fellowship granted to Javier Sanz Rodrigo, Senior Researcher at the National Renewable Energy Center of Spain (CENER). The outgoing phase of this fellowship, from August 2014 to July 2016, was hosted by the National Renewable Energy Laboratory (NREL) of the U.S. Department of Energy. The reintegration phase is back to CENER until July 2017. The project counts with the National Center for Atmospheric Research (NCAR) and the Barcelona Supercomputing Center (BSC) as scientific partners.

The objective is to contribute to the development of an open-source model chain that can bridge the gap between mesoscale meteorological processes and microscale wind farm models.

Data Provider:

The data is based on the Monin Obukhov similarity theory for atmospheric surface layer flows

Data accesibility:

The test case is offered to participants of the IEA Task 31 Wakebench. In the future it will be open for public access.

Site Description:

Monin Obukhov (M-O) similarity theory (Monin and Obukhov, 1954) sets the point of departure of modern micrometeorology (Foken, 2006). It is valid in the surface layer, i.e. approximately in the first 10% of the ABL, where Coriolis effects are negligible compared to friction, and under stationary and horizontally homogeneous conditions with no radiation.

Scope

The benchmark is open to participants of the Wakebench project using surface layer models. This is the first element of the building-block approach so it should be mandatory if you intend to participate in other test cases down the line.

Objectives

Demonstrate that the flow model, when run in M-O conditions, is able to reproduce the analytical expressions of the profiles predicted by the theory for neutral conditions. At the same time, it will be possible to check the compatibility of the wall treatment with the flow model for a range of surface roughness conditions.

Data Accessibility

The benchmark is offered to participants of the IEA Task 31 Wakebench. In the future it will be open for public access.

Input data

The conditions for simulating the M-O profiles in neutral conditions are:

Validation data

Scope

The benchmark is open to participants of the Wakebench project using surface layer models with stratification. This is the first element of the building-block approach so it should be mandatory if you intend to participate in other test cases down the line where thermal stratification is present.

Objectives

Demonstrate that the flow model, when run in M-O conditions, is able to reproduce the analytical expressions of the profiles predicted by the theory for stratified flow. At the same time, it will be possible to check the compatibility of the wall treatment with the flow model for a range of heat flux conditions.

Data Accessibility

The benchmark is offered to participants of the IEA Task 31 Wakebench. In the future it will be open for public access.

Input data

The conditions for simulating the M-O profiles in stratified conditions are:

The New European Wind Atlas (NEWA) project will develop a new reference methodology for wind resource assessment and wind turbine site suitability based on a mesoscale to microscale mode-chain. This new methodology will produce a more reliable wind characterization than current models, leading to a significant reduction of uncertainties on wind energy production and wind conditions that affect the design of wind turbines.

Site Description:

This field campaign provides a unique dataset of wind measurements for validating models for flow over forested hilly terrain. The experiment was conducted on the Rödeser Berg, a hill (380m height) near Kassel, Germany (see Fig. 1). In October 2016, a three month intensive campaign relying heavily on remote sensing devices, i.e. lidar and sodar wind measurement systems, marked the beginning of the experiment. At the same time a one year long-term campaign using two tall masts started.

Background

This challenge is organized in the context of the New European Wind Atlas (NEWA) project, whose overarching goal is to produce a seamless high resolution wind atlas for Europe. The wind atlas methodology will be based on a mesoscale to microscale (meso-micro) model-chain, validated with dedicated experiments as well as other observational databases from public and private sources. Wind resource assessment is related to the development of wind farms and implies the prediction of long-term wind statistics, notably the annual energy prediction (AEP).

Scope

This first phase will be the basis to establish an assessment process for meso-micro wind resource assessment methodologies. To this end, initial datasets from two sites in horizontally homogeneous conditions are proposed:

Cabauw, onshore, and

Fino1 offshore

such that single-column models can be used cost-effectively as proxy for 3D RANS models. This will provide a more efficient approach to test statistical methodologies that can be later applied to heterogeneous sites in 3D.

The results of this benchmark will be anonymous, unless decided otherwise by the participants, both in terms of the name of the participant and the name of the model, to facilitate participation from industry. Of course, it is expected that a subset of modelers will decide to publish their results with a detailed intercomparison in conferences and scientific journals.

Data Accessibility

Data from Cabauw and Fino1 are provided here reformatted to a common standard based on the original data from, respectively, KNMI's CESAR and BSH'x FINO official web repositories.

Data Provider:

Data accesibility:

The test case is offered to all participants of the IEA Task 31 Wakebench.

Site Description:

The wind farm statistics have been measured on a coastal Wind Farm at Nørrekær Enge, Denmark (Højstrup et al., 1993). The wind farm is located in a flat, homogeneous terrain characterized by grassland. The wind farm contains 42 Nordtank NTK 300F 330 [kW] wind turbines, stall controlled with 300 kW rated power. The rotor diameter is 28 m and the hub height is 31 m. The turbines are arranged in 6 rows, each with 7 turbines as shown in Figure 1. Furthermore two 58 m mast, equipped with meteorological sensors in 7 levels, located SW of and inside the wind farm are available.